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Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: suppo
From: |
Konrad Rzeszutek Wilk |
Subject: |
Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D |
Date: |
Tue, 20 May 2014 09:39:33 -0400 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Tue, May 20, 2014 at 05:13:45AM +0000, Chen, Tiejun wrote:
> > -----Original Message-----
> > From: Konrad Rzeszutek Wilk [mailto:address@hidden
> > Sent: Monday, May 19, 2014 9:34 PM
> > To: Zhang, Yang Z
> > Cc: Chen, Tiejun; address@hidden; address@hidden;
> > address@hidden; address@hidden; address@hidden;
> > address@hidden; address@hidden; Kay, Allen M;
> > address@hidden; address@hidden;
> > address@hidden
> > Subject: Re: [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel
> > IGD passthrough with VT-D
> >
> > On Mon, May 19, 2014 at 12:58:50AM +0000, Zhang, Yang Z wrote:
> > > Konrad Rzeszutek Wilk wrote on 2014-05-16:
> > > > On Fri, May 16, 2014 at 06:53:42PM +0800, Tiejun Chen wrote:
> > > > > Some registers of Intel IGD are mapped in host bridge, so it needs
> > > > > to passthrough these registers of physical host bridge to guest
> > > > > because emulated host bridge in guest doesn't have these mappings.
> > >
> > > Thanks for your review for the whole series patch.
> >
> > Sure thing!
> >
> > .. snip..
> > > > > +write_default:
> > > > > + pci_default_write_config(pci_dev, config_addr, val, len);
> > > >
> > > >
> > > > and we just allow it through. But what happens if the guest decides
> > > > to change the BAR sizes? Or fiddle with the GTT?
> > > >
> > > > Ouch. That really looks dangerous - or maybe I am too paranoid?
> > > >
> > >
> > > I do not quite understand your concern. We only pass through PAVPC to
> > physical host bridge. The others are handled by current logic. We don't
> > change
> > any of it. So what problem will be exposed by this patch?
> >
> > Ah, I assumed that pci_default_write_config would be writting everything
> > without any checks. But it looks to be doing the right thing and just sets
> > the
> > emulated values.
> >
> > Could we just add comment saying that it writes to the emulated values? That
> > way it won't trip folks.
>
> diff --git a/hw/xen/xen_pt_graphics.c b/hw/xen/xen_pt_graphics.c
> index 1342f4f..5e5e3d5 100644
> --- a/hw/xen/xen_pt_graphics.c
> +++ b/hw/xen/xen_pt_graphics.c
> @@ -367,6 +367,7 @@ void igd_pci_write(PCIDevice *pci_dev, uint32_t
> config_addr,
> case 0x58: /* PAVPC Offset */
> break;
> default:
> + /* Just sets the emulated values. */
> goto write_default;
> }
>
> @@ -427,6 +428,7 @@ uint32_t igd_pci_read(PCIDevice *pci_dev, uint32_t
> config_addr, int len)
> case 0xa8: /* SNB: base of GTT stolen memory */
> break;
> default:
> + /* Just gets the emulated values. */
> goto read_default;
Thanks!
> }
>
> Thanks
> Tiejun
- Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD, (continued)
- [Qemu-devel] [v2][PATCH 5/8] xen, gfx passthrough: create intel isa bridge, Tiejun Chen, 2014/05/16
- [Qemu-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D, Tiejun Chen, 2014/05/16
- Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D, Konrad Rzeszutek Wilk, 2014/05/16
- Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D, Zhang, Yang Z, 2014/05/18
- Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D, Konrad Rzeszutek Wilk, 2014/05/19
- Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D, Chen, Tiejun, 2014/05/20
- Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D,
Konrad Rzeszutek Wilk <=
- Re: [Qemu-devel] [Xen-devel] [v2][PATCH 6/8] xen, gfx passthrough: support Intel IGD passthrough with VT-D, Chen, Tiejun, 2014/05/19
[Qemu-devel] [v2][PATCH 8/8] xen, gfx passthrough: add opregion mapping, Tiejun Chen, 2014/05/16
- Re: [Qemu-devel] [v2][PATCH 8/8] xen, gfx passthrough: add opregion mapping, Stefano Stabellini, 2014/05/19
- Re: [Qemu-devel] [v2][PATCH 8/8] xen, gfx passthrough: add opregion mapping, Chen, Tiejun, 2014/05/20
- Re: [Qemu-devel] [v2][PATCH 8/8] xen, gfx passthrough: add opregion mapping, Stefano Stabellini, 2014/05/20
- Re: [Qemu-devel] [v2][PATCH 8/8] xen, gfx passthrough: add opregion mapping, Chen, Tiejun, 2014/05/20
[Qemu-devel] [v2][PATCH 7/8] xen, gfx passthrough: create host bridge to passthrough, Tiejun Chen, 2014/05/16